1. Field of the Invention
This invention relates generally to the field of plastic containers, and more particularly to plastic containers that are intended for consumer use and that are fabricated using a blow molding process.
2. Description of the Related Technology
Molded plastic containers for packaging beverages such as orange juice are in wide commercial use throughout the world. Such containers may be fabricated using the extrusion blow molding process, which is typical for containers that are fabricated from a material such as polyolefin, or a stretch blow molding process, which is typical for containers that are fabricated from polyethylene terephthalate, which is commonly known as PET.
When filled with a product, molded plastic containers can be fairly heavy and difficult to handle by some consumers, particularly in the larger sizes. This problem is compounded by any condensation in the form on the exterior surface of the plastic container. Accordingly, it is typical for certain types of plastic containers to be designed with integrated gripping recesses and handles so as to facilitate safety and ease of handling by the consumer.
The configuration of many containers incorporating such gripping recesses and handles is such that a consumer will be induced to grip the container using the forefingers and the thumb in a pinching action that can impart significant compressive forces to the container. While this may facilitate a comfortable and effective manner in which to grip the container from the standpoint of the consumer, the resulting compressive forces, which tend to be concentrated near the recessed grip portions of the container, can result in significant inward deflection and deformation of the container. Such deformation can result in a reduction of the storage volume of the container, causing product to be forced out of the pouring opening of the container in unwanted fashion when the container is full or close to being full. In addition, such deformation can result in a change in the pouring characteristics of the container, either by changing the shape of the dispensing opening itself or the shape of the surfaces that are immediately adjacent to the dispensing opening.
In addition, some plastic containers must be designed to withstand significant pressure differentials between the inside of the container and ambient conditions. Carbonated beverages or malt beverages can generate significant internal pressure, on the order of 45-60 psi for malt beverages such as beer. Beer can be packaged using a cold aseptic or cold filtered process, or it can be pasteurized after filling and capping the container in order to kill any remaining yeast and stop further fermentation of the product. The pasteurization process typically involves spraying the filled and capped containers with hot water until the internal temperatures reach 140-142 degrees Fahrenheit.
Plastic containers may also be designed for use in the hot fill process, which is typically used for packaging beverages such as fruit juices. For such containers, gripping recesses must be designed to withstand pressurization and the subsequent volumetric contraction that occurs during the hot-fill process.
A need exists for an improved plastic container that provides a safe and convenient gripping configuration for the consumer but that exhibits better resistance against deformation than has been the case with conventional designs.